초록 ▼

A feed system for an antenna has a set of inner and outer coaxial waveguides which apply, respectively, both higher and lower frequency radiations to a common radiating aperture provided by a horn and shroud which envelops radiating apertures of the individual feed waveguides. Each of the feed waveg

A feed system for an antenna has a set of inner and outer coaxial waveguides which apply, respectively, both higher and lower frequency radiations to a common radiating aperture provided by a horn and shroud which envelops radiating apertures of the individual feed waveguides. Each of the feed waveguides carries signals having a bandwidth of an octave. Lower frequency radiation to be transmitted by the outer coaxial feed waveguide is applied thereto by a set of four waveguides of a launcher which launches a wave with a desired propagation mode into the outer feed waveguide. Each of the launch waveguides is initially a rectangular double-ridged waveguide for increase bandwidth. The ridging is reduced to a condition of no ridging in the outer feed waveguide by a transition to a single inner ridge which terminates in a tapered star-shaped combination ridge within the outer feed waveguide. Impedance matching rings are slidable within the space between the inner and outer surfaces of the coaxial waveguide for development of a desired standing wave ratio for accurate generation of a desired beam pattern. A dielectric rod is disposed in a forward end of the tube of the inner feed waveguide and protrudes therefrom into the horn for shaping a beam of the higher frequency radiation. A single common phase center is provided for all bands with radiation simultaneously at plural bands.

대표청구항 ▼

[ What is claimed is:] [1.] A radiator for an antenna comprising an elongated cylindrical tube of a first diameter, said tube having a radiating aperture at one end thereof, a second end of said tube being distant from said radiating aperture; andwherein, in the region of the radiating aperture, sai

[ What is claimed is:] [1.] A radiator for an antenna comprising an elongated cylindrical tube of a first diameter, said tube having a radiating aperture at one end thereof, a second end of said tube being distant from said radiating aperture; andwherein, in the region of the radiating aperture, said tube has a neck region enclosing a rod of dielectric material having a dielectric constant different from a dielectric constant of a radiation propagation medium within the tube, said neck region having a second diameter smaller than said first diameter; andan outer surface of the neck region is corrugated to provide a reentrant cavity, a portion of said dielectric rod extends beyond said neck region in a direction away from the second end of said tube, and said dielectric rod has a forward cavity and a rear cavity.